Prostate carcinoma is the most common type of cancer in men. Early detection of prostate cancer when the cancer is confined to the prostate gland has the best chance of cure through radical prostatectomy (surgery). Prostate specific antigen (PSA) is considered as an effective tumor marker and is for most intents and purposes organ specific. However, PSA is not cancer specific. There is a considerable overlap in PSA concentrations in men with prostate cancer and men with benign prostatic diseases. PSA could not differentiate men with organ confined prostate cancer (who would benefit from surgery) from those men with non-organ confined prostate cancer (who would not benefit from surgery). Therefore, PSA is not effective as prostate cancer biomarker in selecting subjects for radical prostatectomy, and identification of new prostate cancer biomarker is needed for the better diagnosis, characterization, and treatment of the prostate cancer.
Villin is the major protein associated with actin of the intestinal microvillus. Its presence has been demonstrated in the brush border of digestive system (esophagus, intestinal, biliary system, and pancreas) and kidney. It has been used as biomarker for neuroendocrine tumors of gastrointestinal tract and lung, and the differential diagnosis between metastatic colonic carcinoma and carcinoma from other organs in human.
A study aimed to the identification of potential biomarkers in prostate cancer serum by protein profiling using antibody microarrays has demonstrated that the level of villin differs significantly between serum samples of prostate cancer subjects and control (Miller J C, Zhou H, Kwekel J, Cavallo R, Burke J, Butler E B, Teh B S, Haab B B: Antibody microarray profiling of human prostate cancer sera: antibody screening and identification of potential biomarkers, Proteomics 2003, 3:56-63). However, for now there has not been demonstrated villin also presents in tissues of prostate and prostate cancer (Goldstein, N S. Immunophenotypic characterization of 225 prostate adenocarcinomas with intermediate or high Gleason scores. Am J Clin Pathol. 2002 March; 117(3):471-7; Hameed, O., Humphrey, P A. Immunohistochemistry in diagnostic surgical pathology of the prostate. Semin Diagn Pathol. 2005 February; 22(1):88-104; Paner G P, Luthringer D J, Amin M B. Best practice in diagnostic immunohistochemistry: prostate carcinoma and its mimics in needle core biopsies. Arch Pathol Lab Med. 2008 September; 132(9): 1388-96).